That's right. There is not just one design that can solve this challenge. All designs so far have some things in comon, but I think that comes naturally in almost every challenge

On the fine tuning part, I've solved all challenges with Snap Values active and when designing new challenges I make it a point to ensure that this is possible.

Btw. out of the 3 solutions I have only 1 only has 4 cells. The others have more. Do you have solutions with 4 cells, Haywire?

The idea of multiple difficulties for a challenge is good! I'd suggest you put that separately into the Suggestions forum However, I don't think it will come soon since it would require reworking and testing all existing challenges. But if Petter is on board, who knows!

Yes there is at least 3 solution, but is there really so much solution possible? I don't think so. I'm almost sure that all 3 solutions already discovered are very close each other. Ok byocyte vs myocite that is the only major difference you will notice. but for example, the moving function I suppose is always made by a ciliocyte. Mitotic propulsion for example is not possible and no flagellocyte. I suppose as well that the "correction" function is always a virocyte that infect the cancer cell. But why don't you let the player use a devorocyte to completely erase the cells? This is what I'm pointing, the solution should be made close to what the level designer expected.

I think you should at first let the player experiment "everything" that would be possible and then reduce the freedom to make the challenge more difficult.

As I said, It is even more frustrating now that we have 40 modes possible. How much challenge yet in the game you can beat using almost 40 mode? I think only a very few, if not none.

I will raise the idea of splitting the challenges into several difficulties cause I think that creating challenge were the difficulties relies more on how to find the right functionalities rather than how to optimise the cells parameter should be the right grow path to motivate the player. Cell optimisation should be the last step only and be part of the "very difficult" level.

Here for example, I think the challenge itself is interesting, even without any limitation (except one inserted cell only). You will still need to be carefull to not change or destroy the healty cells, and still need to find a solution to erase/and or repair "cancer" cells. You can then imagine a lot of solutions, with devorocyte, with virocyte, with eventually stemocyte that change to virocyte or devorocyte when reaching a cancer cell to make the job and then immediately split back to the inactive stemocyte... they will still not be so easy as you have to make a selection on what you change/destroy.
I would have tried such a "big and complex" solution just for fun. Ok I can make it now opening the substrate into the experiment plate but it is a lot less enjoyable than actually play to win an existing challenge and progress into the game.

BenJV4,
I just want to say something in order to sooth your mood.(Maybe) :3
Few months ago, I had a Nanobot concept that can keep spliting as "much" as I want. This is still working. However, I give up this big project because it was really difficult and complex for me on that time. Then I use a 5-cells Nanobot to finish the challenge.
You can find that way~!
Edit: Create a Nanobot with over 20 cells is possible(Or you can set it as your challenge?)

How do you manage to reach 20 cells? or even to have it continue to splits as much as you want?

Maybe the level parameters has changed or I'm wrong but as there is not enough Nitrate on the substrate and no nitrocyte, there is not way to make any organism with 20cells.
16cells is the ultimate maximum because you can make 4 successive splits but then it mean you use every parent cells in the final form.

Reasonably here, I think with 4 splits allowed, you are forced to stay within a 4/5 maybe 6 cells final form. Or you need again to "finetune" the genome to be able to do what you expect (here it is more an optimisation on the parent/child order and function but still laborious).

And I'm not angry, I found a solution as well but I'm convicted that for the majority of people, this level of difficulties and lack of freedom will make them give up after a few attempts... and after a few level, they will give up the whole game...

It definitely need to be more "user friendly" on some aspect of the game and/or in some area. That why I suggest to split all the levels into several difficulties and add restriction progressively.

I understand your feeling (^_^) , it is very normal for many people so I want to share something to you and other people to know another possible solution of this challenge. Moreover, I believe that the meaning of “Annoying Limited Nitrates” is to forcing us to design a simple version of the Nanobot not a massive “NANO”Bot. (Just my thought).
Finally, let me tell you about my way to exceed the spliting limit. Put the Nanobot's egg on the Glueocyte on the side of skin sample, that's how you can get the nitrates from the skin sample. My original design contains a tube which looks like my creation (You can check this out), so that the Nanobot can keep expanding until it reach to the final size.